The Kittila mine is situated within the Kittila Greenstone belt, part of the Lapland Greenstone belt in the Proterozoic-age Svecofennian geologic province. The appearance and geology of the area is similar to that of the Abitibi region of the Canadian Shield. In northern Finland, the bedrock is typically covered by a thin but uniform blanket of unconsolidated glacial till. Bedrock exposures are scarce and irregularly distributed.

The mine area is underlain by mafic volcanic and sedimentary rocks metamorphosed to greenschist assemblages and assigned to the Kittila group. The major rock units trend north to north-northeast and are near-vertical. The volcanics are further sub-divided into iron-rich tholeiitic basalts located to the west and magnesium-rich tholeiitic basalt, coarse volcaniclastic units, graphitic schist and minor chemical sedimentary rocks located to the east. The contact between these two rock units consists of a transitional zone (the "Porkonen Formation") varying between 50 and 200 metres in thickness. This zone is strongly sheared, brecciated and characterized by intense hydrothermal alteration and gold mineralization, features consistent with major brittle-ductile deformation zones. The zone is part of a major north-northeast-oriented shear zone (the "Suurikuusikko Trend").

The Porkonen Formation hosts the Kittila gold deposit, which contains multiple mineralized zones stretching over a strike length of more than 25 kilometres. Most of the work at the Kittila mine has been focused on the 4.5 kilometre stretch that hosts the known gold in mineral reserves and mineral resources. From north to south, the zones are Rimminvuoma ("RimpiS"), the deep extension of Rimminvuoma ("Rimpi Deep"), North Rouravaara ("RouraN"), Central Rouravaara ("RouraC"), depth extension of Rouravaara and Suurikuusikko ("Suuri/Roura Deep"), Suurikuusikko ("Suuri"), Etela and Ketola. The Suuri and Suuri/Roura Deep zones include several parallel subzones that have previously been referred to as Main East, Main Central and Main West. The Suuri zone hosts approximately 5% of the current proven and probable gold reserve estimate on a contained gold basis, while Suuri Deep has approximately 20%, RouraN and RouraC approximately 3%, Roura Deep approximately 41%, Rimpi Deep approximately 24% and RimpiS approximately 7%.

Gold mineralization in these zones is associated with intense hydrothermal alteration (carbonate-albite-sulphide), and is almost exclusively refractory, locked inside fine-grained sulphide minerals: arsenopyrite (approximately 73%) or pyrite (approximately 23%). The remainder is free gold, which is manifested as extremely small grains of gold in pyrite.

Mining at Kittila started initially using the open pit mining method. Open pit mining ended in November 2012 and all mining is currently carried out underground via ramp access.

At the Kittila mine, the Suurikuusikko, the Rouravaara and the Rimpi orebodies are currently mined by underground mining methods accessed via ramp. Approximately 5,000 to 5,500 tonnes of ore per day are fed to the processing plant. The underground mining method is open stoping with delayed backfill. Stopes are between 25 and 40 metres high and yield between 8,000 and 40,000 tonnes of ore per stope. To ensure sufficient ore production is available in the future to supply the mill, 15,000 to 17,000 metres of tunnels will be developed each year. After extraction, stopes are filled with paste backfill or cemented backfill to enable the safe extraction of ore in adjacent stopes. Ore is trucked to the surface crusher via the ramp access system.

On February 14, 2018, the board of directors of the Company approved the construction of a 1,044 metre deep shaft, a processing plant expansion as well as other infrastructure and service upgrades.

At year-end 2021, total progress on the shaft sinking project was approximately 70% complete. Shaft sinking is expected to be completed in the second half of 2022. Commissioning of the production hoist is expected in late 2022 or early 2023.

Ore is processed in a 6,000-tonne per day surface processing plant that was commissioned in late 2008, and expanded from 3,000 to 3,750 tonnes per day in 2014 and further expanded to 6,000 tonnes per day in 2020.

The mill expansion involved installation of a secondary crushing circuit, new thickener and reactor capacity, and minor modifications to the existing grinding circuit and autoclave.

The ore at the Kittila mine is treated by grinding, flotation, pressure oxidation and CIL circuits. After grinding, ore processing consists of two stages. In the first stage, ore is enriched by flotation and, in the second stage, the gold is extracted by pressure oxidation and CIL processes. At the end of the second stage, gold is recovered from the carbon in a Zadra elution circuit and recovered from the solution using electrowinning and finally poured into dore bars using an electric induction furnace.